The following is from a post I made to a different list regarding the Simplex Criterium Levers.
"When I dismantled, to clean them, I detected a lighter feel to the Lever. Upon weighing, I found that the 'Early' lever weighed 13 grams, and the 'Later' 30 grams. A dramatic difference. After weighing the COMPLETE units (levers and all mounting Hardware) the weight was 72 grams vs. 107 grams. Also, the finsh washer directly behind the wing nut is made of light alloy, not a metal stamping as on the later version."
"The later levers have a shoulder where the plastic ends. That was probably incorporated to keep the plastic from sliding down the lever and splitting apart at the top."
"The 'Early' Levers are UNchromed or UNanodized Alloy as are the washers (they polished up easily). The 'Later' levers, a heavier Base metal (?) are chromed."
Comparison photos can be found here:
http://s517.photobucket.com/
This 'Wing' logo appears to have been replaced with the "Sun" logo in the very early 70's along with the heavier lever. Clamp styles and logos also changed.
Jay Dubiel
Halifax, VA USA